Berlin 2014 – scientific programme
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A: Fachverband Atomphysik
A 6: Clusters (with MO)
A 6.1: Talk
Monday, March 17, 2014, 10:30–10:45, BEBEL SR144
Infrared spectroscopy of doped silicon clusters — •Nguyen Xuan Truong, Marco Savoca, André Fielicke, and Otto Dopfer — Institut für Optik und Atomare Physik, TU Berlin, Germany
Doped Si clusters are investigated with resonant infrared-ultraviolet two-color ionization (IR-UV2CI) combined with global optimization and DFT calculations. Neutral SimXn clusters are irradiated with tunable IR light from a free electron laser before being ionized with UV photons from an F2 laser. Resonant absorption of IR photons leads to an enhanced ionization efficiency for the neutral clusters and provides the size-specific IR spectra. Structural assignment of the clusters is achieved by comparing the calculated linear absorption spectra of the most stable isomers with experimental data. For SimCn (with m+n=6), we found the systematic transition from chain like geometries for C6 to 3D structures for Si6 [1]. For further first row doped Si6X (with X = Be, B, C, N, O) clusters, additional properties have been calculated, such as binding and ionization energies, and natural bond orbitals. All X dopant atoms in Si6X have a negative net charge suggesting that Si atoms act as electron donors within the clusters. Moreover, the overall structures of Si6X strongly depend on the nature of the dopant atom (size and valency). While for some of the most stable Si6X clusters one Si atom in the original Si7 structure is simply substituted (X = Be, B, C), other cases exhibit a completely different geometry (X = N, O).
[1] M. Savoca, A. Lagutschenkov, J. Langer, Dan J. Harding, A. Fielicke, O. Dopfer, J. Chem. Phys. A 117, 1158 (2013).